Human breast sarcoma and human breast implantation: A time trend analysis based on SEER data (1973-1990)

Since the demonstration in the 1940s of foreign body induction of sarcomas in rodents, the safety of artificial implants in humans has been a matter of concern. In this study, we assess the risk for the development of breast sarcomas in women with silicone breast implants. Our analysis is based on the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program database for the years 1973-1990 and on estimates of breast implantation rates from about 1960 onward. We have divided the SEER data into two equal time periods, 1972-1981 and 1982-1990. For each time period, we estimated the average annual number of women in the United States who had received breast implants 10 or more years earlier. This analysis allows for a 10 year latency period for the induction of breast sarcoma. We calculated that the average number of women in the U.S. 10 or more years post breast implantation was 55,000 for the 1973-1981 period and 509,000 for the 1982-1990 period. We then examined the SEER data to observe whether there was a concomitant rise in the female breast sarcoma incidence rates between these two time periods. We found the mean age-adjusted incidence rate of breast sarcomas was 0.13 per 100,000 women for the initial 9-year period, 1973-1981, and 0.12 per 100,000 women for the latter 9-year period, 1981-1990. Although the number of person-years at risk (women at least 10 year post augmentation) was more than 9 times greater in the latter period, there was no concomitant increase observed in the breast sarcoma rates. Based on this ecological study, we conclude that there is no evidence of an increased risk of breast sarcomas associated with the use of silicone breast implants.